[ubuntu-uk] Login/Logout Scripts

[Andrew Oakley]

Rob Beard wrote:
> We'd also like a script to run at logoff to reset the users password (so 
> they can't just log back on for another hour without asking first).  For 
> this I was thinking of a script to reset the password using passwd.
...
> I see in /etc/gdm there are two directories call PostLogin and 
> PostSession, has anyone actually used these?

Yes, me.

/etc/gdm/PostLogin/default is called directly after graphical LOGIN 
before the graphical session starts (ie. it is a login script)

/etc/gdm/PostSession/Default is called directly after graphical LOGOUT.

I use /etc/gdm/PostLogin/Default to erase and re-create (from tar.gz) my 
guest account on my laptop, so that well-meaning but annoying geek 
friends who insist on "improving" the guest desktop setup, have their 
efforts wiped at the next subsequent login.

You sound like you want /etc/gdm/PostSession/Default instead.

In case you also want to wipe and re-create the entire account, I have 
supplied my /etc/gdm/PostLogin/default , /usr/local/bin/loadguest and 
/usr/local/sbin/saveguest scripts too. They are public domain.

> as root after login, so I wonder if I could run  my autologoff script 
> from there and at the end of the autologoff script have a line that 
> resets the password?  (I presume any scripts executed from the Default 
> script will run as root too?)

Yes and yes.

Consider chown root.root and chmod 750 to prevent the users cat'ing the 
script to discover the password.

-- 
Andrew Oakley

===== /etc/gdm/PostLogin/Default =====

#!/bin/bash
if [[ "$LOGNAME" == "guest" ]]
then
   /usr/local/bin/loadguest
fi

===== /usr/local/bin/loadguest =====

Note that you can supply a parameter, the username. If absent it assumes 
"guest". Remember to chmod 755 this script.

#!/bin/bash
# Goes in /etc/gdm/PostLogin/Default
# This script erases & re-creates a user home directory that has
# previously been saved with saveguest
username=$1
if [[ "$username" == "" ]]
then
   username=guest
fi
if [[ -f /home/$username.tar.gz ]]
then
   cd /home
   rm -rf $username/*
   tar xvfz /home/$username.tar.gz
else
   echo "/home/$username.tar.gz does not exist or is not a regular file"
fi

===== /usr/local/sbin/saveguest =====

Note the s in sbin! Must be RUN AS ROOT once you have set up the account 
the way you like it AND LOGGED OUT OF THAT ACCOUNT (if you don't log 
out, nasty things are left lying around like xauthority). Remember to 
chmod 755 this script.

Note that you can supply a parameter, the username. If absent it assumes 
"guest".

#!/bin/bash
username=$1
if [[ "$username" == "" ]]
then
   username=guest
fi
if [[ -d /home/$username ]]
then
   cd /home
   mv -f $username.tar.gz $username-old.tar.gz
   tar cvfz $username.tar.gz $username
else
   echo "/home/$username does not exist or is not a directory"
fi